1. Field
Embodiments of the invention relate to spatial extent migration for tiered storage architecture.
2. Description of the Related Art
Tiered-storage architectures refer to systems in which there are different types of storage designated to be in different tiers. For example, the following are examples of tiers of storage:                1—solid state drives        2—enterprise class hard disk drives        3—Serial Advanced Technology Attachment (SATA) or lower performance hard disk drives        4—magnetic tape        
In current tiered-storage architectures, extents are migrated from tier-to-tier dynamically based-upon Input/Output (I/O) profiling. An extent may be described as a contiguous area of storage in a computer file system that is reserved for a file. A file may be stored in one or more extents. Also, one extent may store multiple files. In current tiered-storage architectures, the extents that are accessed for I/O most frequently are stored in faster access storage (e.g., solid state drives and hard disk drives), while extents that are accessed for I/O less frequently are stored in slower access storage (e.g., SATA and magnetic tapes).
Although the current implementation has a lower performance impact to storage systems and improved Quality Of Service (QOS) during migration because migration is more predictable, the current implementation is not optimal.
Typically, when an I/O threshold is reached, the extents are migrated between tiers of storage, as needed. However, this technique is not optimal as it would be preferred that the extent migration occurred prior to reaching the I/O threshold as performance is impacted by the migration.
Thus, there is a need for improved spatial extent migration for tiered storage architecture.